Are you talking deep stack cash, hyper turbo sng, cap limit cash, live, online, etc?
I bet there are probably a dozen people who could make worthy claims of being the best hu player. A few names that would be in contention are probably Doug Polk, Isuldur1, Daniel Cates, Oliver Busquet, JHub, Ben Sulsky, Ike Haxton, and probably 3 germans that live in their moms basement. There are also probably 25 guys that really have the GTO down pat and could give a lot of the guys on the list above a run for their money.